Biology Reference
In-Depth Information
Q Every now and then when I'm going through farm country, I see a huge flock of
songbirds wheeling through the air in what looks like a big black cloud. What are
they, and why do they fly that way? How come they don't crash into each other?
A
You're looking at a flock of European Starlings, famous the world over for that won-
drousflying.Whentheygetintothatamazingflockformation,chancesarethere'sahawk
nearby. Hawks are reluctant to get too close to one of these swarms, partly because of
the unpredictable changes of direction the birds make and partly because the birds are so
close together that the hawk risks colliding with one while grabbing another.
How do the birds within one of these swarms avoid each other? There are still mys-
teries involved, but we do know a few things thanks to high-speed photography, which
allows us to slow the action. Birds seem to key in not on their immediate neighbors but
on more distant birds, so the smoothness in changes happens the same way sports fans
produce a “wave,” by watching the people more in the distance and anticipating the right
momenttoact.Noparticularbirdinaswarmistheleader.Anyindividualcanbeginanew
maneuver, banking toward the center of the group, and that movement spreads through
the flock like that wave.
